You know how almost every startup’s pitch has a save-the-world bent to it? Well, maybe not this one.

Apollo Fusion, a space startup funded in part by $10 million from LinkedIn cofounder Reid Hoffman, is reportedly planning to fuel its rockets with mercury, according to a Bloomberg report. Yes, that mercury, the neurotoxin that even in tiny doses can impair a person’s cognitive functions, lower IQ, damage motor skills, and decrease memory. The same mercury that NASA left far behind because of its toxic, dangerous side effects and potential contamination of our already struggling environment. Apparently Apollo wants to bring it back.

Four anonymous sources who spoke to Bloomberg said the company’s engineers were keen on using mercury because “its performance is better than that of alternatives like xenon or krypton.”

In an email to Fast Company, Apollo Fusion’s CEO, Michael Cassidy, said, “We are committed to maintaining a low impact on the environment with all of our work. We don’t comment on our proprietary technology due to competitive risks, either on innovations that we’ve built or things that we’re testing.”